The purpose of this study was to develop criteria for the design and use of earth-covered metal shells for rapidly emplaceable fighting bunkers. Fighting bunker dimensions were determined from bunkers commonly used by U. S. forces in Korea and Vietnam. An initial concepts study verified that the bunker shell to most efficiently support the earth and explosion loads and meet the minimum dimensional requirements could be made from Multiple Intersecting Cylindrical Shells (MICS). Corrugated steel shells of various thicknesses, corrugation dimensions, and joining methods were designed with the MICS concept and evaluated in laboratory static tests and field explosion tests. A fighting bunker shell was designed and tested that: (a) can be fabricated in battlefield rear areas or by small vendors from standard corrugated steel culvert sections, (b) weighs approximately 300 pounds, (c) can be installed over an unlined (in most soils) fighting hole by non-engineer troops without mechanized equipment, and (d) when properly covered with earth will defeat the effects of direct hits of the contact bursts of large mortars and medium artillery rounds.